Cloudflare is the canonical example of why you can't vibe-code infrastructure. Knowing that this optimization was even necessary, let-alone having the ability to build it, is something that doesn't become apparent until you're operating at considerable scale. Once there, of course if you're Cloudflare, you use coding agents to build it. But outside of these temples of scale, good luck even knowing it was needed.

If you work at a SaaS of any kind, I think it's worthwhile considering what things will look like when scale is the only thing that is really defensible anymore.